This invention relates generally to a vehicle cab ventilating system and more particularly concerns cab ventilating systems which control the temperature of the air entering the operator enclosure.
With the recent emphasis on shielding a vehicle's operator from the effects of airborne dirt and the extreme air temperature ranges in which the vehicles, such as tractors and other off the road vehicles, must operate, these vehicles are being equiped with cabs that have heating/air conditioning systems. Examples of these systems are found in U.S. Pat. Nos. 3,555,846, 3,626,713 and 3,868,896.
The systems described in these patents suffer from the weaknesses that have plagued the conventional systems since they were first introduced. The first weakness lies in the fact that the conventional systems do not have sufficient insulation of the temperature control system from the extreme temperature variances to provide an efficient temperature control system.
The second weakness is twofold, and arises from the fact that the air flow from the filter to the operator enclosure is sealed at the interface of large pieces formed from sheet metal. This sealing process is both ineffective and extremely costly to produce, because the massive size of the passage produces an incredibly long interface that must be sealed, while the violent nature and extreme temperature range of the working environment of the vehicle unduly shortens the effective life of the seal.
It is therefore an object of the present invention to provide a vehicle cab temperature control system which increases the efficiency of the system by effectively insulating the temperature control system from the extreme variances in the temperature of the vehicle's operating environment.
Moreover it is an object of the present invention to provide such a system with an effective seal between a temperature control system, and the dirt and temperature variances of the vehicle's working environment.
Finally, it is an object of the present invention to provide the vehicle cab temperatue control system described above that can be economically produced by the manufacturer of the vehicle.